1. Field of the Invention
The present invention relates to a keyboard, and in particular, to a keyboard having additional function keys.
2. Description of the Prior Art
Computers are now a mainstay in every person""s life. The incorporation of multimedia functions with a conventional computer have significantly increased the power, popularity and usage of computers. Multimedia peripheral equipment, including but not limited to CD-ROMs and DVD players, are now often used with computers to provide multimedia effects on the monitor, speakers and other peripherals associated with the computer.
Despite the increased multimedia usage, computer systems and their associated peripherals are still controlled by conventional and well-known input devices such as keyboards and computer mice. To operate a multimedia device (e.g., xe2x80x9cPLAYxe2x80x9d, xe2x80x9cFast Forwardxe2x80x9d, xe2x80x9cSTOPxe2x80x9d, etc.), a user would still need to press the appropriate buttons and switches on the multimedia device.
In addition, a user often needs to input a series of instructions or key presses to execute certain applications. For example, to sign on to the Internet, a user may need to press a sequence of keys, or execute a sequence of mouse clicks.
To improve the user""s convenience, efforts have been made to provide hot keys or additional function keys to a conventional QWERTY keyboard so that the user can control and manipulate multimedia devices via a single key on the keyboard, or execute certain applications through a single key on the keyboard. Unfortunately, a conventional QWERTY keyboard is normally provided with 108 key codes. After deducting the keys for designated language and system commands from the 108 key codes, there only remains eight keys that can be further defined. As a result, the conventional QWERTY keyboard is limited in its ability to provide additional function keys.
To address this drawback, U.S. Pat. No. 5,986,586 to Tsai provides an additional I/O port to form a new scan matrix for the keyboard. This is illustrated in FIG. 1, where a microprocessor A1 is connected to a new I/O port A2 to form a new 9xc3x9716 scan matrix, which is different from a conventional 8xc3x9716 scan matrix. The additional I/O port A2 adds an additional 16 keys A3 to the conventional scan matrix. Unfortunately, the additional I/O port A2 in U.S. Pat. No. 5,986,586 to Tsai poses certain problems. For example, this can only be implemented when the microprocessor A1 has an extra I/O port to connect the additional scan line, so its applicability can be limited to certain microprocessors. As another example, increasing the size of the conventional scan matrix may lead to the possibility of error in executing a defined function or procedure.
It is an object of the present invention to provide a keyboard that allows the user to define a number of function keys.
It is another object of the present invention to provide a keyboard that increases the number of function keys.
In order to accomplish the objects of the present invention, the present invention provides a keyboard having a processor, a scan matrix coupled to the processor, a first set of keys coupled to the scan matrix, a logic control circuit, and a second set of keys coupled to the logic control circuit. The processor decodes the identity of a pressed key from the second set of keys via the logic control circuit.